Is there a uniform way of getting the bitrate from a netstream.
I know I could extract it from the tags that come with the stream but
this might give some problems, the bitrate tagfield name is not the
same for all servers I believe and for example this streamhttp://cal.icecast.net:8630/prog1.ogg has a bitrate that says icy-br (14):Quality -0.40

There’s no uniform way of getting the bitrate without playing the stream unless you can parse what the different servers give you. If you call FSOUND_Stream_Net_GetStatus while the stream is playing then you can get the current bitrate – this is good for showing the bitrate in realtime i.e. it changes over time for VBR streams.